Wireless cardioresonance stimulation

ABSTRACT

An apparatus for the cardio-synchronised stimulation of skeletal or smooth muscle, but excluding the heart muscles, in a counterpulsation mode of a patient. The apparatus comprises an active and a passive electrode for attachment to said patient, a signal processor having a configuration input for varying a time delay associated with counterpulsation mode stimulation, and a sensing system for sensing information relating to the performance of the patient&#39;s heart and for transmission of information signals to said signal processor, said signal processor producing control signal information relating to stimulation signals to be applied to said active electrode in a counterpulsation mode, a stimulation signal generator Associated with said active electrode for generating stimulation signals, wireless transmission means for transmitting said control signal information from said signal processor to said stimulation signal generator whereby said stimulation signal generator applies stimulation signals to said active electrode in accordance with said signal information.

CROSS-REFERENCES TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/032,168, filed Sep. 19, 2013, now U.S. Pat. No. 8,812,118, which is adivisional of U.S. patent application Ser. No. 11/667,622, filed Dec.14, 2007, now U.S. Pat. No. 8,577,471, which claims the priority ofInternational Patent Application PCT/EP2005/009384, filed Aug. 31, 2005,which claims the benefit of European Patent Application 04027227.0,filed Nov. 16, 2004, the disclosures of which are hereby incorporated intheir entirety by reference for all purposes.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for thecardio-synchronized stimulation of skeletal or smooth muscle, butexcluding the heart muscles, in a counterpulsation mode of a patienthaving a heart and a cardiovascular system. The patient can be a humanbeing or another mammal such as a race horse, or could also be anotheranimal having a heart and a cardiovascular system such as a kangaroo(kangaroo hearts in good condition can be used for valve replacement inhumans).

References in the following to a patient will cover all the foregoingand does not imply the patient is suffering from ill health, sincetreatments using the present invention can be applied to persons oranimals which are not ill but for which a desire exists for improvementin some aspect of their physical or mental condition.

Apparatus and methods of this kind are, for example, described in theInternational patent application with the publication number WO01/013990.

The applicants have established that the apparatus and methods describedin the above mentioned document WO 01/013990 can be used to advantagefor a large number of different applications. A prime application of theapparatus and methods described is improving the condition of the heartof a patient, for example to reduce the likelihood of a heart attack, orto improve the condition of the heart following a heart attack, or toassist the patient in recovering following bypass surgery, or to treatpatients with chronic diseases, in particular chronic heart failure andpatients suffering from demetabolic syndrome. In addition it has beenfound that the treatment can be used with minor modifications in orderto improve blood flow to various parts of the body and to improve lymphdrainage from various parts of the body. Moreover, it has been shownthat the treatment can be used to improve the general condition of awide variety of patients, such as those who are ill or recovering fromillness. A wide range of other applications are also known and describedin WO 01/013990.

BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to improve the apparatus andmethods described in the document WO 01/013990, and in particular toprovide a very flexible system which enables a patient to be treated asan outpatient, and indeed also over a long period of time while thepatient goes about his normal daily life. It is a further object of thepresent invention to provide apparatuses and methods which enable thetreatment to which any particular patient is subjected to be variedflexibly and for this treatment to take account of developments in thistype of treatment which occur during the course of time and which areexpected as practical experience in the use of the apparatus and methodsgrows and the database of successful treatments becomes larger.

A yet further object of the present invention is to minimize thephysical size of the apparatus which is associated with the patient, sothat it is of light weight, is compact, is easily carried, is reliableand does not hinder the patient in any significant way and so that, forexample, the batteries involved have a long working life.

A yet further object of the present invention is to provide an apparatusand methods which enable the patient's reaction to the treatment he isreceiving to be monitored remotely and preferably for the treatment tobe modified or interrupted if monitoring shows that the treatment is notideally suited to the particular patient's needs.

In order to satisfy the above object there is provided, in accordancewith the present invention, an apparatus of the initially named kindcomprising:

at least one active electrode and at least one passive electrode adaptedfor attachment to said patient,

a signal processor preferably having an associated configuration inputfor varying at least a time delay associated with counterpulsation modestimulation

a sensing system for sensing information relating to the performance ofthe patient's heart and for transmission of information signals to saidsignal processor,

said signal processor being adapted to produce control signalinformation relating to stimulation signals to be applied to said atleast one active electrode in a counterpulsation mode,

a stimulation signal generator associated with said active electrode forgenerating stimulation signals

wireless transmission means for transmitting said control signalinformation from said signal processor to said stimulation signalgenerator whereby said stimulation signal generator applies stimulationsignals to said active electrode in a counterpulsation mode inaccordance with said signal information.

The information relating to the performance of the heart is typicallyselected from the group comprising: heart rate information, ECGinformation, ECG derived information, ECG information and informationresulting from electrical stimulation, ECG derived trigger signals, R-Rinformation, end of T-wave information, blood pressure information andblood pressure derived information.

The sensing system can include at least one of an invasive sensor, anintercavity sensor, a non-invasive sensor, a body surface sensor and aremote sensing system detached from the patient's body.

If a remote sensing system is provided, the signal processor can beintegrated into said remote sensing system. The sensing system ishowever preferably adapted for wireless transmission of said heartinformation to said signal processor.

Alternatively, the sensing system can be adapted to transmit said heartinformation to a medical evaluation unit associated with the signalprocessor and the medical evaluation unit is then preferably adapted totransmit signal configuration information to the signal processor sothat said signal processor takes account of said configurationinformation when generating said control signal information.

Apparatus of the above kind has the advantage that wireless transmissionfrom the signal processor to the stimulation signal generator enablesthe signal processor to be located remote from the patient and for thestimulation signal generator to be made compact and small because theprocessing capacity necessary to generate the trigger signals for thestimulation signal generator is located in the separate signal processorand does not have to be carried by the patient. In addition, thebatteries associated with the stimulation signal generator carried bythe patient do not have to provide the power for the operation of thesignal processor and can therefore be made smaller and lighter.

It is particularly beneficial if the sensing system for sensinginformation relating to the performance of a patient's heart and fortransmission of information signals is adapted for wireless transmissionof said information signals, either to the signal processor directly orpossibly via the medical evaluation unit. If such wireless transmissionis used from the sensing system then the patient is completely free ofcables connecting him (or her) to the associated apparatus, such as themedical evaluation unit and the signal processor.

For the purpose of the present invention it is sufficient if the sensingsystem for providing information relating to the performance of theheart simply detects the R-peaks of the patient's heart rhythm andestablishes the time at which these peaks occur in order to predict fromthem the end of the T-wave of the heart rhythm for each successiveheartbeat, so that stimulation can be carried out at or close to thepredicted end of the T-wave, i.e. in the counterpulsation mode. Suchinformation can be delivered by an electrocardiograph orelectrocardioscope but is basically also available from a simple set ofECG electrodes which can be combined with a simple light-weight monitor.Equally, devices are known, such as the “Polar”™ belt or wrist-mountedblood pressure detectors which also reliably provide signal tracesrelated to the patient's heart rhythm and from which information on theR-R peaks and/or the end of the T-wave can be derived. There are alsocertain remote sensing systems which can deliver correspondinginformation.

If electrical detection is used, for example using ECG electrodes, thenthis has the benefit that the electrical stimulation applied to thepatient can also be picked up by the ECG electrodes and can be displayedsuperimposed on the trace of the patient's heart rhythm. In this way thesynchronization of the electrical stimulation with the patient's heartrhythm and its effect on the patient's heart rhythm can be betterassessed.

It is possible for the sensing system to have its own transmitter fortransmitting information relating to the performance of the patient'sheart to the signal processor, or to a medical evaluation unitassociated with the signal processor, and for the stimulation signalgenerator to have an antenna for receiving trigger signals andoptionally other information from the signal processor.

It is also possible for the transmitter of the sensing system and thereceiver of the stimulation signal generator to be combined into atransceiver which is carried by the patient and which is, for example,connected by wires to the sensing system and to the stimulation signalgenerator. Such transceivers are readily available, for example in theform of a mobile phone. Mobile phones also have the advantage that theyhave significant signal processing power, so that relevant software canbe stored in them as can data relating to the patient's heart rhythm andthe performance of the heart and data relating to the stimulationapplied or to be applied. Automatic programs can then allow thetransmission of such information to a medical evaluation unit atintervals for assessment by a medical practitioner monitoring a numberof different patients at the medical evaluation unit. Moreover, it isnot essential for a skilled medical practitioner to carry out allevaluations. It is also conceivable for programs to be drawn up whichenable at least routine checking to be carried out with a medicalpractitioner only being alerted if something appears to be amiss.

The signal processor can itself also be realized as a mobile phone or asa dedicated unit similar thereto. This facilitates communication from,for example, a mobile phone associated with the signal sensing systemand/or the stimulation signal generator since these two systems, i.e. amobile phone associated with the sensing system and/or the stimulationsignal generator and a mobile phone associated with a signal processor,are inherently compatible. Again, the processing power available in anymodern mobile phone system is sufficient for storage of the softwareprograms needed by the signal processor in order to analyze theinformation coming from the sensing system, to predict the times atwhich the ends of the T-waves occur and to generate the requisitetrigger signals for onward transmission to the stimulation signalgenerator. If the signal processor is realized as a mobile phone it canbe carried by the patient—without the patient being wired to thephone—and the mobile phone forming the signal processor can receive viaits inbuilt antenna signals transmitted from an antenna of the sensingsystem (or from the stimulation signal generator) and can transmitcontrol signals to the stimulation signal generator.

A further advantage of using a mobile phone or a mobile phone-likesystem is that communication with any other mobile phone ormobile-phone-like system involves a telephone number which can be usedto uniquely identify the party with which communication is to beestablished and the party from whom a communication is received. Thus,one signal processor can communicate with a plurality of differentstimulation signal generators, and indeed with a large number of them,and can provide different trigger information and other information toeach of them based on the particular needs of the user or on theparticular needs of the associated stimulation signal generator.

It is not necessary for this communication to take place simultaneouslywith a plurality of users but instead the relevant information can besent batch-wise at discrete times to the individual users. For example,once a timing scheme of trigger signals has been established it can beretained for a period of time so long as the patient's heart rhythmremains substantially constant. Thus, trigger timing information sent bythe signal processor to the stimulation signal generator can be storedin a memory of the stimulation signal generator and used cyclically totrigger the electrical stimulation. Since the stimulation signalgenerator can readily communicate with the sensing system it is alsopossible for the timing established by the signal processor to beretained and repeatedly used by the stimulation signal generator toapply stimulation to the patient until the sensing system providingheart information shows that something has changed and needs to bereflected by a change in the timing of the trigger signals. Once thishappens, the signal processor can be automatically called up to providechanged timing.

It is particularly beneficial that the medical evaluation unit givesmedical practitioners the possibility of changing the program used bythe signal processor to generate the timing signals. In this way thetiming signals supplied by the signal processor to the stimulationsignal generator can be adapted in accordance with the patient's needsas assessed by the medical practitioner.

It is particularly favorable if the medical evaluation unit is alsorealized by incorporating elements of a mobile phone so thatcommunication can take place directly between the medical evaluationunit and the stimulation signal generator. For example, should themedical practitioner sense personally, or in response to an alarm signalgenerated at the medical evaluation unit, that a treatment being used ona particular patient is not satisfactory or is potentially dangerous,e.g. because of some event, such as an accident, then the ability existsto switch off the stimulation signal generator directly, thus preventingfurther treatment until such time as the problem has been remedied.

The medical evaluation unit can also be adapted for wirelesstransmission of the configuration information to said signal processor.

In an alternative embodiment the heart information produced by thesensing system can be sent not to the medical evaluation unit but ratherby wireless transmission to the signal processor and the signalprocessor can be adapted to transmit said heart information to themedical evaluation unit (by wire or by wireless transmission). Likewisethe medical evaluation unit can then be adapted to transmit signalconfiguration information to the signal processor by wire or by wirelesstransmission and the signal processor then takes account of saidconfiguration information when generating said signal information.

In a particularly preferred embodiment a plurality of active electrodesis provided, each having a respective stimulation signal generator, andthe signal processor is adapted to transmit a respective control signaluniquely associated with one of said active electrodes to each saidstimulation signal generator. For example, the active electrodes caneach have a respective stimulation signal generator connected theretovia a respective lead.

Alternatively, a respective lead can be provided for each activeelectrode and means can be associated with a single stimulation signalgenerator for applying stimulation signals to said active electrodes insequence via said leads.

When the signal processor has a single transmitter adapted to transmitcontrol signal information to a plurality of stimulation signalgenerators, means are provided for uniquely associating particularcontrol signals with a respective one of said stimulation signalgenerators.

Alternatively, the signal processor can have a plurality of transmitterseach adapted to transmit control signal information to a respective oneor group of said stimulation signal generators. In the latter case meansare provided for uniquely associating particular control signals with arespective one of said stimulation signal generators.

The signal processor is preferably adapted to transmit control signalinformation for a train of stimulation signals applied to an activeelectrode, said control signal information being selected from the groupcomprising:

amplitude of the stimulation signals,frequency of the stimulation signals,duration of the train of the stimulation signals, width of theindividual stimulation signals of the traindelay of the train of the stimulation signals relative to a referenceselected for counterpulsation stimulation anda recognition code by which said stimulation signal generator recognizesthat said control signal information is intended for it.

As indicated above, means is preferably provided at said stimulationsignal generator or at each said stimulation signal generator forstoring control signal information relating to any respectivelyassociated active electrode.

It is particularly beneficial when means is provided at said signalprocessor for transmitting to said stimulation signal generator at leastone of a program for processing said control signal information, anysubsequent changes to said program and a new program for processing saidcontrol signal information.

The or each said stimulation signal generator preferably includes atleast some of the following items:

its own controller,its own clock,its own receiver antenna (RX),a power circuit anda battery.

It is especially beneficial when the or each said stimulation signalgenerator includes at least one of the following additional items:

a transmitter (TX),means for data storage,means for program storage and asignal generator trigger.

An especially beneficial realization of the invention involves providingthe or each said stimulation signal generator with a program and/orhardware providing a wake mode, a sleep mode and a death mode. With suchan arrangement the battery associated with the stimulation signalgenerator only delivers significant amounts of power during the wakemode, but not during the sleep mode from which it can be awakened orduring the death mode from which it can no longer be awoken other thanby changing or recharging the battery. Such a stimulation signalgenerator can be switched on and off during even one heartbeat in orderto save power and this increases the working life of the battery priorto changing it or recharging it.

It is particularly expedient when a display is provided at least one ofsaid signal processor, said stimulation signal generator and a medicalevaluation unit associated with said apparatus, said display being forthe display of said heart information signals.

The display can also be adapted to display data representing an image ofthe electrical stimulation applied to said patient. The display ispreferably adapted to display one of an actual ECG-trace and arepresentation of an ECG-trace with said image of the applied electricalstimulation superimposed thereon.

When a medical evaluation unit is provided it preferably also has anassociated printer for printing said display data.

The said sensing system is preferably also adapted to send timingsignals to said stimulation signal generator or generators. This enablesthe synchronization of the trigger signals (especially the storedtrigger signals referred to above) with the patient's heart rhythm to bechecked.

The sensing system includes a non-electrical sensor and transmits datafrom said non-electrical sensor to said signal processor. Such a systemavoids the electrical stimulation applied to the patient beingincorrectly interpreted as heart information.

The sensing system includes an associated signal processor and atransmitter. This enables the signal processor (which can again be partof the mobile phone or of a mobile phone related unit) to compress theheart information and information on electrical stimulation applied tothe patient prior to transmission to the signal processor or the medicalevaluation unit.

The sensing system can conveniently include at least one of an A/Dconverter, a data storage memory and a data compressor. At least one ofsaid A/D converter, said data storage memory and said data compressorcan be embodied in said associated signal processor.

When the sensing system includes a data compressor for compressinginformation for transmission to said signal processor or said medicalevaluation unit into packages, the signal processor and/or the medicalevaluation unit is adapted to assemble said data packages into acontinuous data stream, optionally in the form of an ECG-trace withsuperimposed electrical stimulation signals.

A respective code is preferably uniquely associated with each of saidsensing system, said signal processor and said electrical stimulationsignal generator or generators, so that each item can be uniquelyidentified.

The electrical stimulation signal generator preferably has an associatedpower supply in the form of a battery and a boost converter.

A method of operating an apparatus for the cardio-synchronizedstimulation of skeletal or smooth muscles, but excluding the heartmuscles, in a counterpulsation mode on a patient having a heart and acardiovascular system, comprising the steps of using a sensing systemproviding heart information from the patient to communicate said heartinformation by wireless means to at least one of a signal processor anda medical evaluation unit adapted to input configuration data to thesignal processor and the step of using the signal processor to sendtrigger data to one or more stimulation signal generators adapted toapply electrical stimulation signals to electrodes provided on or in thepatient.

The signal processor can send the trigger data, i.e. the control signalinformation, to said one or more stimulation signal generators bywireless transmission.

Preferred variants of the apparatus and of the methods are set out inthe claims and in the further description.

The invention will now be described in more detail by way of exampleonly and with reference to the accompanying drawings in which are shown:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a first schematic diagram illustrating the operation of thepresent invention in accordance with a first embodiment,

FIG. 2 is a diagram similar to FIG. 1 of a second embodiment of thepresent invention,

FIG. 3 is a further diagram similar to FIG. 1 of a third embodiment ofthe present invention,

FIG. 3A is a diagram related to that of FIG. 3 but showing bidirectionalwireless communication between a configuration input for a signalprocessor and the signal processor,

FIG. 4 is a fourth diagram similar to FIG. 1 showing a fourth embodimentof the present invention,

FIG. 5 is a schematic diagram similar to FIG. 4 showing a possiblealternative version of the embodiment of the FIG. 4,

FIG. 6 is a further diagram similar to FIG. 4 showing a yet furtheralternative embodiment of the present invention

FIG. 7 is a further schematic diagram related to FIG. 4 but showing ayet further embodiment of the present invention,

FIG. 7A is a diagram related to that of FIG. 7 but showing thepossibility of bidirectional wireless transmission between a medicalevaluation unit and a signal processor,

FIG. 7B is a diagram similar to FIG. 7A but showing the signal processorconnected by a lead to or integrated with a stimulation signalgenerator,

FIG. 8 is a schematic diagram showing a first embodiment of a boostconverter capable of use for the present invention to increase theoutput voltage of a battery to a higher voltage for electro stimulationpurposes,

FIG. 9 is a schematic diagram of a second boost converter similar tothat of FIG. 8 but further modified for the purposes of the presentinvention,

FIG. 10 is a schematic diagram of a stimulation signal generator usefulfor the present invention and operable with either the circuit of FIG. 8or the circuit of FIG. 9,

FIG. 11A is a schematic diagram representing an ECG trace taken from apatient with electrical stimulation pulses superimposed thereon, thisbeing a diagram which can be displayed at the sensing system, at amedical evaluation unit associated with the sensing system or at asignal processor associated with the sensing system,

FIG. 11B is a diagram showing an enlarged scale the shape of twosequential biphasic pulses of the electro stimulation pulses shown inFIG. 11A,

FIG. 12 is a schematic diagram explaining the operation of the boostconverter of FIG. 8,

FIG. 13 is a schematic diagram explaining the operation of the boostconverter of FIG. 9,

FIGS. 14A and 14B are diagrams showing a simulation signal generatorconnected to a pair of active and passive stimulation electrodessuitable for use in any of the embodiments of the present invention, andindeed in a plan view (FIG. 14A) and in a side elevation (FIG. 14B),

FIG. 15 is a diagram showing a patient provided with four pairs ofactive and passive electrodes,

FIGS. 16A and 16B are diagrams similar to FIG. 11A but showing how thestimulation signals are applied to each pair of active electrodes inturn, the diagram of FIGS. 16A and 16B corresponding to FIGS. 6 and 8 ofthe international application published as WO 2005/044373, and

FIGS. 17A and 17B are diagrams corresponding to FIGS. 5A and 5B of WO2005/044374 showing one possible scheme of electrical stimulationprovided to one pair of active and passive electrodes for one heartbeatof a patient.

DETAILED DESCRIPTION OF THE INVENTION

In the embodiments of the different figures, the same reference numeralswill be used to identify components which are identical to each other orhave the same function. It will be understood that the description givenfor any component having a particular reference numeral in any one ofthe figures also applies to any component having the same referencenumeral in any other figure, unless something is stated to the contrary.

Turning first of all to FIG. 1 there can be seen an apparatus 10 for thecardio-synchronized stimulation of skeletal or smooth muscle present onor in a person 12, or on or in another patient such as a racehorse or onor in an animal, the said person, patient or animal having a heart and acardiovascular system. The skeletal or smooth muscle can in principle belocated anywhere on the body of the patient.

The stimulation is effected typically via electrodes such as 14, 16,e.g. in the manner described in the international patent applicationwith the publication number WO01/013990, or in the manner described inthe international patent applications published as WO 2005/044373,WO2005/044374 and WO 2005/044372, or in the EP application EP04026453.3,all filed on Nov. 8, 2004, the contents of which are incorporated hereinby reference.

The apparatus 10 comprises the following items:

at least one active electrode 14 and at least one passive electrode 16adapted for attachment to the patient 12 being treated,

a signal processor 18 having an associated configuration input 20 forvarying at least the time delay associated with the counterpulsationmode stimulation,

a sensing system 22 for sensing information relating to the performanceof the patient's heart and for transmission of information signals tothe signal processor 18, the signal processor 18 being adapted toproduce control signal information relating to stimulation signals to beapplied to said the least one active electrode 14 in thecounterpulsation mode,

a stimulation signal generator 24 associated with the at least oneactive electrode for generating the stimulation signals which areapplied to the at least one active electrode and

wireless transmission means 26 embodied in or associated with the signalprocessor 18 for transmitting the control signal information from thesignal processor 18 to a receiver 27 at the stimulation signal generator24.

In this way the stimulation signal generator 24 applies stimulationsignals to the at least one active electrode in the counterpulsationmode in accordance with the control signal information received from thesignal processor 18.

The information relating to the performance of the heart can be ofdifferent types and can, e.g., be selected from the group comprising:heart rate information (for example from a “Polar” Belt™), ECGinformation (e.g. from an electrocardiograph or electrocardioscope), ECGderived information, ECG information and information resulting fromelectrical stimulation, ECG derived trigger signals, R-R information,end of T-wave information, blood pressure information (e.g. from a bloodpressure monitor) and blood pressure derived information.

The said sensing system 22 can include at least one of an invasivesensor, an intercavity sensor, a non-invasive sensor, a body surfacesensor and a remote sensing system detached from the patient's body.

The operation of the individual items listed above will now be explainedin more detail. As noted above the stimulation is applied in thecounterpulsation mode as described in the above referenced WO01/013990.Basically speaking this means that the initial electrical stimulation isapplied to the patient at a time corresponding to the end of the T-waveof the patients heart rhythm and more specifically in a time windowlying within a range of 5% of the R-R path before the end of the T-waveand 45% of the R-R path after the end of the T-wave.

The precise time at which the initial stimulation is applied via theelectrodes to the patient in synchronization with the patient's heartrhythm relative to the end of the T-wave is referred to as the delay.This delay is said to be negative if the stimulation is applied at atime lying within the range of 5% of the R-R path before the end of theT-wave and is positive if the delay is applied within the range of 45%of the R-R path after the end of the T-wave. It is zero if the initialstimulation corresponds with the end of the T-wave. Instead of measuringthe delay with respect to the end of the T-wave it is more convenient tomeasure it from the preceding R-peak, in which case it is alwayspositive.

It will be appreciated by those skilled in the art that the concept ofR-R path lengths, corresponding to the distance between successiveR-peaks of the heart rhythm, e.g., as displayed on an electrocardiogram,and the point in the electrocardiogram referred to as the end of theT-wave are well established terms in the medical field. They are shown,for example, in FIG. 11A and in FIG. 16B. Furthermore, it will beunderstood that the actual length of the R-R path, e.g. expressed inmilliseconds, is inversely proportional to the patient's heart rateprevailing at any one time and is subject to considerable variationdepending on the condition of the heart and on whether the patient is atrest or is exercising, or is excited, is nervous or performing strenuoustasks. The end of the T-wave can be predicted from the times at whichthe R-peaks occur using the so-called Bazett relationship or byreference to tables of statistics for various categories of persons orpatients. When using cardiostimulation in accordance with the presentteaching it is necessary to predict, from historical values of the R-Rpath length, e.g. from the immediately preceding R-R path length, orfrom a recent average value of the R-R path lengths of several precedingheart beats, when the end of the next T-wave will occur and to time thetriggering of the electrical stimulation signals to occur at or near tothe predicted end of the T-wave using the appropriate delay.

Ways of predicting the end of the T-wave from past R-R values and adiscussion of the difficulties which arise can be found in theaforementioned publication WO 2005/044373. In addition the applicationpublished as WO 2005/044374 describes the way a muscle contraction canbe prolonged with benefit by applying additional electrical musclestimulating pulses during each heart beat after the initial stimulatingpulse. The application published as WO 2005/044372 describes anapparatus and method by which the electrical stimulating pulses arevaried in accordance with a predetermined pattern or randomly in orderto avoid a muscle or muscle group to which stimulation is applied for along time from becoming fatigued. All these techniques require a signalprocessor such as 18 to determine the timing of the individualelectrical stimulating pulses relative to the patient's actual sensedheart rate or rhythm.

As will be explained later it would be unusual to provide just a singleactive electrode. The prior proposals of the present applicants usuallyinvolve four active electrodes associated with a group of muscles and astimulation signal is applied to each active electrode in turn so thateach active electrode receives a stimulation signal every four heartbeats. This helps avoid the muscles becoming fatigued or too accustomedto the applied stimulation. Although some of the attached figures showonly one active electrode 16, generally a plurality of active electrodesis present as will be explained later. However, the present teachingcould be used with just one active electrode. The concept of usingmultiple active electrodes will be described later with reference toFIGS. 15, 16 and 17

It is convenient for the signal processor 18 to deliver trigger signalswhich trigger the generation of the actual electrical stimulationsignals applied to the patient in the stimulation signal generator. Onedesign for a stimulation signal generator is given in the EP applicationEP04026453.3, the content of which is also incorporated herein byreference. Another stimulation signal generator will be described later.

By providing the signal processor 18 separately from the stimulationsignal generator 24 it is possible to standardize the stimulation signalgenerator 24 and to reduce its size so that it can be carried by thepatient without being a burden to the patient and without inhibiting hisactivities in any way. Achieving a further reduction in size of thestimulation signal generator with a simultaneous improvement in itsperformance is another aim of the present teaching. Yet another aim ofthe present invention is to enable one stimulation signal generator tobe connected to each pair of active and passive electrodes 14 and 16 sothat with a plurality of active electrodes 14 a like plurality ofstimulation signal generators 24 is present.

Moreover, by adding intelligence to the signal processor 18 it can bemade very flexible and adapted to deal with a variety of differentcircumstances. It can also be reprogrammed to take account of the latestfindings, e.g. so as to implement particularly beneficial pulse timingsor pulse profiles or particularly beneficial courses of treatment,without having to change the apparatus carried by the patient.

Equally one signal processor 18 can be used with a variety of differentsensing systems 22 and can be adapted or updated to derive theinformation needed from the respective sensing system 22, by processingthe signal output from that system to enable the correct timing of thetrigger pulses used to trigger electrical stimulating pulses at thestimulation signal generator 24 (or stimulation signal generators if aplurality of them are present). In addition the signal processor can bedesigned to deliver trigger pulses in the millivolt range whereas thestimulation signal generator delivers electrical stimulating pulses witha substantially higher amplitude, say up to 50 volts.

A large number of different variants of the above described basicapparatus can be realized. For example, as indicated in FIG. 2, when aremote sensing system 22 is provided, the signal processor 18 can beintegrated into said remote sensing system 22 or connected to it by alead 23. The communication between the remote sensing system 22 and thesignal processor could, however, also take place via a transmitter 28and a receiver 30 as indicated in dotted lines in FIG. 2.

Because remote sensing systems are not yet well developed it is howeverpreferred to use a sensing system 22 which is attached to the patientand it is then preferred for said sensing system 22 to be adapted forwireless transmission of said heart information to the signal processor18. This can be achieved by a wireless transmitter 28 embodied in orassociated with the sensing system 22 and an antenna 30 embodied in orassociated with the signal processor 18, as shown in FIG. 1.

However, as indicated in FIG. 3, even if a sensing system or unit 22 isused which is attached to the patient, i.e. is not a remote sensingunit, the signal processor 18 could still be integrated into the sensingsystem or connected to it by a lead 23. Another possibility, which couldbe used in all embodiments and which is shown in FIG. 3A, is for thesignal processor 18 to be adapted to receive at the receiver 30configuration information transmitted to it from a transmitter 46 at theconfiguration input. As a further option, a receiver 38′ can be providedat the configuration input, e.g. to receive information from the signalprocessor 18 or from a medical evaluation unit. This has the advantagethat the configuration input 20 can, for example, include a keyboard anda display screen of useful size which is present at a location remotefrom the signal processor which is carried by the patient, so that thepatient is free to move unencumbered by the keyboard and screen. Thewireless connection between the configuration input 20 and the signalprocessor 18 and/or between the configuration input 20 and the medicalevaluation unit 32 can be realized by a mobile phone, a personal digitalassistant with phone function, or any device with transmitter and/orreceiver capabilities, or any standard piece of equipment having atransceiver, a microprocessor, a memory for storing software and data, abattery, or other source of power and a clock.

It can also be beneficial if in accordance with FIG. 4, the sensingsystem is adapted to transmit said heart information to a medicalevaluation unit 32 and the medical evaluation unit 32 is adapted totransmit signal configuration information to said signal processor 18,with the signal processor 18 taking account of said configurationinformation when generating the control signal information.

The medical evaluation unit can be a computer, e.g. a suitablyprogrammed PC, or can take the form of an information presentationsystem viewed by a skilled operator who then provides input informationto the signal processor—e.g., via the configuration input 20, ordirectly via an input at the medical evaluation unit which passes viathe lead 34 to the signal processor 18—to ensure the appropriatestimulation signals are triggered at the stimulation signal generator.

The configuration input 20 is adapted to input all parameters to thesignal processor 18 which are necessary for it to generate the requiredoperating or trigger signals for the stimulation signal generator(s) 24.The medical evaluation unit, which can be connected to the configurationinput 20 (or communicate with it wirelessly), may well have a need tocheck the operating data currently input at the configuration input 20,and thus the configuration unit 20 is designed to make the requiredinformation available to or accessible by the medical evaluation unit32. Equally, it may be useful for the signal processor 18 to not onlyreceive operating parameters from the configuration input 20 (or fromthe medical evaluation unit 32) but for the actual operating parametersbeing used by the signal processor to be available to or accessible bythe configuration input 20 and/or the medical evaluation unit 32, sothat transmission of said operating data from the signal processor 18 tothe configuration unit 20 and/or to the medical evaluation unit 32 isalso preferably provided for.

More specifically, the medical evaluation unit 32 is adapted to displayand/or print out the signals from the sensing system, e.g. in the formof an electrocardiogram, or simply in the form of a succession of R-Rpeaks possibly together with entries showing the positions of theT-waves or the predicted ends of the T-waves, together with signalsrepresentative of the applied stimulation. This enables a skilledoperator viewing the display to control the signal processor, either bysignals input by him at the medical evaluation unit or at the signalprocessor (optionally at the configuration input or another dedicatedinput) to change the stimulation treatment applied to the patient. Ifthe medical evaluation unit 32 is realized as a computer or includes amicroprocessor—which will normally be the case—then it is preferablyprogrammed to control the signal processor to generate trigger signalsfor triggering the stimulation signal generator(s) to apply theappropriate stimulation signals to the patient. The position at whichthe control signals from the medical evaluation unit enter the signalprocessor can also be considered to be a configuration input.

In the example of FIG. 4 a non-remote sensing system 22 is used, i.e.one attached to the patient and signals from the sensing system 22 aretransmitted by a lead 25 to the medical evaluation unit 32. As mentionedthe medical evaluation unit 32 is connected via a lead 34 to the signalprocessor 18. As before, the signal processor 18 transmits the timingsignals for the electrical stimulation pulses via the transmitter 26 tothe receiver 27 at the stimulation signal generator.

It is, however, preferable for the medical evaluation unit 32 to beadapted for wireless transmission of said configuration information tosaid signal processor 18 as shown in FIG. 5. This can be done by meansof a transmitter 36 at the medical evaluation unit which communicateswith a receiver 30 at the signal processor or a receiver 38′ at theconfiguration input 20. In an alternative (not shown) the receiver 30can be integrated with the transmitter 26 and configured as atransceiver. This arrangement enables the medical evaluation unit andthe signal processor to be housed in different rooms and indeed atcompletely separate remote locations. For example, the medicalevaluation unit could be located in a special facility in a hospital andthe signal processor in a doctor's practice in a different building,town or country. It is particularly preferable if, as shown in FIG. 6,the sensing system is adapted to transmit said heart information to saidmedical evaluation unit by wireless transmission. For this purpose thesensing system 22 has a transmitter 28 and the medical evaluation unit areceiver 38.

This variant has the advantage that the patient can be completely mobileand located a considerable distance from both the medical evaluationunit 32 and the signal processor 18. The patient only needs to carry onhis person the sensing system 22 with transmitter 28 and the stimulationsignal generator(s) 24 with receiver 27. Both the sensing system (22)and the stimulation signal generator(s) 24 can be made very small, sothat the patient's mobility is not hindered and he can be subjected tolong-term treatment while going about his daily life. In the variantshown in FIG. 6 the receiver 38 and the transmitter 36 at the medicalevaluation unit can be combined into a transceiver. Even if the patientcarries the signal processor 18 in the form of a mobile phone on hisperson, which is one possibility, this does not hinder him undulybecause he is not wired to the phone.

It would also be possible to combine the signal transmitter 28 at thesensing system 22 and the signal receiver 27 at the stimulation signalgenerator 24 into a single transceiver. Moreover, the stimulation signalgenerator and the sensing system could be integrated into a singledevice as indicated by the dotted outline 40 in FIG. 6.

One particularly favorable realization of such a single device would bea dedicated unit which would, for example, take the form of a mobilephone, a personal digital assistant with phone function or any standardpiece of equipment having a transceiver, a microprocessor, a memory forstoring software and data, a battery or other source of power, a clockand the necessary interface(s) for connection to the sensor or sensors21 at the patient, such as ECG sensors, and to active and passiveelectrodes 14, 16. The dedicated unit could also include a screen fordisplaying a trace symbolizing and relating to the positions of the R-Rpeaks and the end of the T-wave and possibly a signal relating to thestimulation applied. The realization as a mobile phone is particularlyattractive since a mobile phone has all the necessary elements of thededicated unit, or could be provided with additional interfaces ifnecessary. In particular a mobile phone has plenty of storage capacityfor storing software and data relating to the additional functions ithas to perform for implementing the present teaching. Indeed it could befurther developed to function as a heart monitor and provide timelywarnings to a receiver at, e.g., the medical evaluation unit, if a heartattack is incipient—enabling remedial action to be taken at an earlystage, e.g. in a telephone call from an operator at the medicalevaluation unit to the patient concerned, or by alerting an emergencyservice.

Moreover, the signal processor 18 can also take the form of a dedicatedunit which could, for example, take the form of a mobile phone, apersonal digital assistant with phone function or any standard piece ofequipment having a transceiver, a microprocessor, a memory for storingsoftware and data, a battery or other source of power, a clock and aninput for configuration data and/or control signal information. It couldalso comprise a mobile phone related unit having one or more signalreceivers, transmitters in addition to a telephone aerial or aerials.

In another variant shown in FIG. 7 the sensing system 22 transmits heartsignal information to the signal processor 18 and the signal processoris adapted to transmit or relay heart information to the medicalevaluation unit 32 via a lead 44 and said medical evaluation unit isadapted to transmit signal configuration information to said signalprocessor via the lead 34. The signal processor 18 then takes account ofthe configuration information when generating said signal information.

In an alternative shown in more detail in FIG. 7A the signal processor18 is adapted to transmit said heart information to said medicalevaluation unit 32 by wireless transmission as indicated by the receiver38 shown in dotted lines at the medical evaluation unit and the medicalevaluation unit 32 is adapted for wireless transmission of saidconfiguration information via the transmitter 36 to the receiver 30 atthe signal processor 18. In this case the receiver 30 and thetransmitter 26 can form one transceiver and the receiver 38 and thetransmitter 36 can form a second transceiver. Again the transmitter 28and the receiver 27 can also be combined into a transceiver and alltransceivers can be realized as a mobile phone or as a mobile phonerelated unit.

FIG. 7B shows possible further modifications of the embodiment of FIG.7A. In one modification the configuration input 20 communicates with thesignal processor 18 by wireless transmission, as discussed in connectionwith FIG. 3A and/or with the medical evaluation unit 32 by wirelesstransmission. For example, the transmitter 46 at the configuration input20 can communicate with the receiver 30 at the signal processor 18and/or with the receiver 38 at the medical evaluation unit 32. Moreover,the transmitter 26 at the signal processor can transmit information tothe receiver 38′ at the configuration input 20. The receiver 38′ at theconfiguration input can alternatively or additionally receiveinformation from the medical evaluation unit by wireless transmissionfrom the transmitter 36 provided at the medical evaluation unit 32. Forexample, the medical evaluation unit could reset the parameters of thestimulation being applied to the patient by sending new configurationdata either directly to the signal processor 18 or via the configurationinput 20 and could also send a message to the configuration input 20advising the patient of the changed parameters when he views or switcheson the screen associated with the configuration input 20.

Furthermore, FIG. 7B shows by way of the line 48 that the signalprocessor could also be connected by a lead to the stimulation signalgenerator(s) 24. If a plurality of stimulation signal generators 24 arepresent, then the signal processor 18 could be connected to one or moreof them by a lead and the other signal generators could either beinterconnected by leads or communicate with each other wirelessly.

In a further alternative the signal processor could be integrated withall or one of the stimulation signal generators 24 and could communicatewirelessly with each stimulation signal generator 24. In these cases,i.e. when the signal processor is connected by a lead to one or morestimulation generators 24 or is integrated with one or more of them, thesignal processor 18 is physically carried by the patient. This is not aproblem because the signal processor 18 can be made very small andrequires little power to drive it. This power can readily be supplied bythe battery associated with each stimulation signal generator. It islater described with reference to FIGS. 14A and 14B how a stimulationsignal generator can be used for each pair of active and passiveelectrode 14, 16 and can, for example, be clipped to them. It isentirely possible and indeed sensible to integrate the signal processor18 into one of the stimulation signal generators 24 or possibly to havea signal processor 18 integrated into each of the stimulation signalgenerators 24. This would make it possible to use one standardintegrated component (stimulation signal generator+signal processor) foreach pair of electrodes with economy of scale due to the need tomanufacture only one standardized device. Moreover, since eachstimulation signal generator has its own battery, the individualbatteries can be kept relatively small and the distributed weight is nota problem for the patient.

In addition, it should be noted that the embodiment of FIG. 3A can alsobe modified to include a medical evaluation unit 32 communicating withone or both of the configuration input 20 and the signal processor 18 bywireless transmission (optionally bidirectional as discussed inconnection with FIG. 7B).

As mentioned above one of the objects of the present invention is toimprove the design of the stimulation signal generator to make itlighter, compacter and to improve the working life of the batteries thatare used. One way of achieving this is to avoid a bulky and heavytransformer for the power circuit.

The reasoning behind the concept is as follows: At low battery voltageVo and at a given maximum stimulation end voltage Vmax of a powercircuit, the transformer can become too bulky and too heavy, because theratio of the transformer would have to be increased to reach Vmax, themore Vo is being reduced. As an example: at Vo=7.4 V and at Vmax=45 V, astandard transformer ratio of, e.g., 1:10 can be used by increasing theoutput voltage from 5 V to 50 V, allowing Vmax of 45 V withoutdistortion. At Vo of 1.2 V a ratio of 1:50 would have to be used toincrease the output voltage from 1.0 V to 50 V, allowing Vmax of 45 Vwithout distortion. Such a transformer would be inordinately heavy. Thebasic solution provided by the present invention is to use a boostconverter which is shown in FIG. 8 It consists of an inductor 50 “L”, adiode 52 “D”, a capacitor 54 “C”, a switching component 56 “So” and aboost controller 58. In an improved version of the boost converter asecond switching component 60 “Soo” shown in FIG. 9 is used which isconnected to the battery voltage supply Vo, and to ground, GND. Thecomplete circuit shown in FIG. 10 further involves a switching set up,e.g., the form of a so-called H-Bridge involving the switches S1, S2,S3, S4, is connected to the two outlets (+Vx and GND) to allow thedesired switching to be controlled by an H-Bridge controller. Inintegrated circuits, the voltage V0 from the battery is nowadaystypically equal to 1.2 V.

Any switching component can be used for the switches So, Soo, S1, S2, S3and S4, such as electronic analog switches, transistors, triacs, etc.,whatever is best suited for micro integration to keep dimensions small.There are many ways how such a booster converter can be switched. Thefollowing describes one specific example. The description below shows,as a preferred example, how a desired constant voltage signal, a fullybalanced plus/minus signal as shown in the impulse diagram of FIG. 11,can be achieved to be applied to a patient using a booster converter.

The diagram of FIG. 11 shows in FIG. 11A a typical e.c.g. trace with therepeating signal elements QRSTPQR . . . as well known to anycardiologist. Superimposed on this trace and starting at the end of theT-wave; i.e. after the time QT in FIG. 11A is a stimulation signalcomprising a first train of pulses having a duration D with twosequential pulses of this train (which are representative of all thepulses) being shown to an enlarged scale in FIG. 11B. it is noted thatthe relative amplitudes of the pulses in FIG. 11A are to differentscales. In practice the amplitude of the stimulation pulses during theinterval D is in the range up to ±45 volts whereas the peak amplitudesof the R-peaks are of the order of millivolts.

The graph of FIG. 11B shows how the impulse signal Vp varies as afunction of time (with time being shown to an expanded scale relative toFIG. 11A). The pulses of FIG. 11B are so-called biphasic pulses. That isto say the impulse signal Vp increases from zero to a maximum with arelatively sharp rise time, dwells at the peak amplitude for a timeessentially equal to W/2, then drops sharply to a minimum value at whichit persists for a further time equal to W/2 following which it returnsto zero and remains at this level for a period Tb prior to repeatingagain. Thus, the desired biphasic signal is essentially a rectangularwave signal with positive and negative components of balanced amplitude,with the pulses having a duration W shorter than the pulse interval Tb.This signal results in a minimum net electrical loading of the patientand a minimum net consumption of energy to achieve a particular musclecontraction and maintain it for a period of time which is actuallygreater than D and up to two to three times the duration D. Particularlypreferred excitation signals are described in WO2005/044374.

To achieve the positive constant voltage flank of FIG. 11B using thecircuit of FIG. 8 the switching component So is switched continuously bythe boost controller to build up in small digital steps to the desiredmaximum voltage V as shown in FIG. 12 as one of the parameters set bythe controller to the signal generator and thus to the boost controllerin order to regulate the desired constant output voltage +Vx, for theduration D of the package of impulse trains, see the impulse diagram ofFIG. 11A. For this purpose the boost controller has a feedback of theeffective voltage Vc of the capacitor C from the positive outputcompared to ground “GND” so it can regulate the value Vx to become andstay constant at the set value Vs. The boost controller uses a clock(not shown) to open and close the switching component So at highfrequency.

Initially, the H-Bridge controller closes switches S2+S4 (S1+S3 areopen). The active and passive electrodes (14, 16) are connected to GNDand Vp on the patient=0 V. At the desired time Td (2), the controllercloses switch S3+S2 (S1+S4 are open). As a consequence +Vx is connectedto the active electrode 14 on the patient and the GND is connected tothe passive electrode 16 on the patient. A current corresponding to theactually prevailing voltage difference Vp and the resistance andcapacitor value of the human body flows between the electrodes.

Because the switch So is continuously closed and opened and closed andopened at the frequency determined by the boost controller, and becausethe diode D prevents current flowing back, the capacitor is charged andincreased in its voltage each time the switch So is opened and, as aconsequence, the voltage on the patient Vp is incrementally increased(3) until after time Tx the set voltage Vs is equal to the voltage Vx,so the voltage on the patient now has become Vp=+Vx (4). The voltagegradient increase is proportional in time to the frequency of theswitching of So and the voltage steps are proportional to the selectedsteps. Typically, a 1 MHz boost controller 58 could e.g., boost thevoltage from 0 V to 50 V in 20 steps per volt, each requiring oneswitching step in the time Tx of 1 milliseconds (50 V times 20steps/V=1000 steps; 1000 steps divided by 1′000′000 steps/sec=0.001 secor 1 millisecond.

The switching component So continues to be switched with S3+S2 beingclosed (S1+S4 are open) to recharge the capacitor in order to compensatethe current flowing to the patient. The voltage +Vx=Vp is applied to theactive electrode 14 of the patient and the corresponding current flowsfor the desired time Tw.

To achieve the negative constant voltage flank at the desired time Tw1(5), the H-Bridge controller switches instantly and closes S1+S4 (S3+S2are now open): Now the active electrode 14 on the patient is connectedto GND and the passive electrode 16 becomes −Vx, because the voltage Vcon the capacitor cannot jump. The voltage on the patient Vp is now thenegative voltage −Vx and a corresponding current now flows from thepassive electrode to the active electrode. This inversion of the voltage+Vx at the output of the boost converter is indicated in FIG. 12 by thedotted line. The diagram shows that the output of the boost converteralways stays at the constant level +Vx, however it is the switching ofthe H-Bridge, which reverses the effect Vp on the patient. The boostcontroller continues switching the switch So and the negative voltage−Vx is being kept on the patient for a second period Tw2 (6). This ishow an identical, but inverted (negative) signal can be produced simplyby switching the H-Bridge correspondingly.

After period Tw2 has elapsed, the H-Bridge is now switches at point (6)and closes S2+S4 (S1+S3 are open). Now passive and the active electrodes16, 14 are now again connected to GND and the human capacitor isdischarged instantly and with this the voltage Vp on the patient dropsimmediately to zero. Switching of So can now either rest to save batterypower or it continues to be switched and with this the capacitor keepsits charge for a break corresponding to the period Tb (7).

After the period of the break Tb (7) (the break is being calculated asthe interval time I, minus impulse width W (see FIG. 11B) has elapsed,the H-Bridge controller switches closes switch S3+S2 (S1+S4 are open).Now the charged capacitor can discharge instantly the positive voltage+Vx=Vp to the patient and the process described above resulting inpositive and negative flanks is repeated.

After the period of the duration D has ended with a last switching ofthe H-bridge closing S2+S4 (8), hereby connecting both the active andpassive electrode to GND and Vp=0, So switching can be stopped and thecapacitor can either be discharged by closing S1+S2, for instantdischarging of the capacitor, or alternatively, the capacitor maintainsits charge until the next set value Vs defines whether the voltage hasto be increased or decreased.

So for the next impulse of trains the process can be started again todesign a constant voltage signal having the same or a differentamplitude A. When the capacitor has not been discharged it can beboosted to the newly desired level (up or down).

Using such a boost converter and an H-Bridge any signal can be designedas a function of time at the outputs. The example described and shown issimply given as one possible example.

The preferred embodiment of the boost converter and its operation willnow be described with reference to FIGS. 9 and 13.

As noted above, the FIG. 9 embodiment includes an additional switchingcomponent Soo in comparison to FIG. 8 and this switching component Soois provided and is also switched by the boost controller when required.

The setup works in principle in exactly the same manner as describedwith reference to the embodiment of FIG. 8, except that, for achievingthe positive flank for the first time, the switch Soo of the positivebooster converter is opened meaning that the designed positive flank ofthe voltage increase to Vx cannot be delivered to the active electrode14 and the built up voltage Vx is stored in the capacitor. At thedesired time Td2 (9), Soo is closed and the stored voltage Vx isinstantly delivered to the active electrode, without the design-relateddelay Tx. The buildup of the desired voltage +Vx in the capacitor has tobe done prior to the time Td−Tx to allow an instant delivery of the fullvoltage Vx.

All other steps remain the same as described with reference to FIGS. 8and 12.

It remains to be said, that some effort is required to integrateswitching component Soo into a micro integrated circuit, but there areways how it can be done. Although the diagram of FIG. 13 is ideal, it isacceptable to use only the setup of FIG. 12 as an acceptable compromise.

As indicated above a plurality of pairs of active/passive electrodes 14,16 are preferably provided and each pair of active/passive electrodes14, 16 has its own stimulation signal generator 24 or power circuit 24so that reference will be made here to multiple power circuits. Eachpower circuit of the multiple power circuits is placed directly onto arespective pair of active and passive electrodes, placed in the vicinityof each other onto the patient's skin avoiding the need for wiringbetween a power circuit unit and the electrodes. One terminal of eachelectrode is used to connect and carry the respective power circuit unitthus keeping the wiring to a minimum. Each stimulation signal generator24 is equipped with switching components to form a so-called H-Bridge,S1-S4 and one boost converter is powered from a battery of a designvoltage V0 as described above with reference to FIG. 8 or FIG. 9.

The stimulation signal generator receives three different pieces ofinformation. First of all it receives

A) delay information, i.e. the exact moment when the power circuit hasto stimulate relative to the heartbeat, from the signal processor 18 viathe transmitter 26 of the signal processor and the receiver (RX) 27 ofthe stimulation signal generatorB) parameters, i.e. combinations of amplitude, frequency, duration,signal width of single or multiple trains of stimulation packages fromthe data storage 60, where these parameters are stored. Such parametersare received via the receiver RX, whenever a corresponding new parameteris being sent by wireless communication from the signal processor 18.The delay information can also be stored in the memory or data storage60 if it remains substantially constant and can be updated as required(depending e.g. on the patient's heart rate) from the signal processor18.C) the boost controller 58, having a clock (not shown), which controlsthe signal generator and the H-Bridge controller 64 in such a way, thatthey can deliver the wanted signal with the stored parameters at thecorrect delay time.

Thus, the receiver RX 27 receives from the transmitter 26 of the signalprocessor 18 addressed (coded) wireless information:

-   -   a correct delay for each heartbeat,    -   parameters whenever they have been changed, and    -   sleep and wake up information in order to put the signal        generator to sleep when not required in order to save battery        power

The stimulation signal generator 24 preferably includes a transmitter TX(which may be the transmitter 28 or could be a separate transmitter) canprovide feedback information to the signal processor (e.g. via thereceiver 30) such as:

-   -   information on whether the stimulation signal generator is        asleep or awake (ready to receive parameters)    -   confirmation that a parameter change has been received and        stored information on the remaining battery capacity etc.

Each power circuit unit (stimulation signal generator 24) has its ownwireless communication means (antenna), common or separate for RX and TX(e.g. 27, 28), depending on the means of wireless communication.

Turning now to FIGS. 14A and 14B there can be seen a pair of active andpassive electrodes 14, 16 which are provided with terminals 70, 72 ontowhich a respective stimulation signal generator 24 is clipped so that ithas electrical contact to the two terminals 70, 72. The stimulationsignal generator 24 can, for example, be designed as shown in FIG. 10and can have its own antenna 74 which can be simply a receiver antenna27 as shown in FIG. 10, or an antenna for a combinedreceiver/transmitter 27, 28 which is also indicated in FIG. 10.

Turning now to FIG. 15 there can be seen four pairs of active andpassive electrodes 14′, 16′; 14″, 16″; 14′″, 16′″; 14″″, 16″″″, eachprovided with a respective stimulation signal generator 24′, 24″; 24′″,24″″. Instead of providing each stimulation signal generator 24 with itsown antenna 74, which can be a receiver antenna or a transceiverantenna, each of the stimulation signal generators could be connected toa transceiver 76 illustrated here in the form of a mobile phone, andindeed via leads 78′, 78″, 78′″, 78″″. Equally, if a mobile phone isused in this way it can be connected to the ECG electrodes 21′, 21″,21′″ or to any other suitable sensing system. Again, the connection inthis case is by way of leads 80′, 80″, 80′″. Because the leads 78′, 78″,78′″, 78″″ and 80′, 80″ and 80′″ are optional they are shown in brokenlines. Since very light leads can be used they do not pose a significantinconvenience for the patient

FIGS. 16A and 16B now illustrate how the pairs of active and passiveelectrodes are energized. It is noted that FIG. 16B refers to channels1, 2, 3 and 4 which are the channels which are associated with the fourelectrode pairs 14′, 16′; 14″, 16″; 14′″, 16′″; 14″″, 16″″″ and theassociated stimulation signal generators 24′, 24″; 24′″ in FIG. 15.

The channels 5, 6, 7 and 8, which are an optional extra, could beassociated with four further pairs of active/passive electrodes withassociated stimulation signal generators (not shown). As described in WO2005/044373, such systems can be used to improve blood transport todifferent areas of the body or to improve lymph transport from variousareas of the body. In order to achieve such transport it is necessaryfor the electrical stimulation signals in the group of channels 5 to 8to be offset from those in the channels 1 to 4. This will not beexplained further here because the concept is described and claimed indetail in the above referenced PCT application.

The schematic representation of an ECG trace at the top of FIG. 16Bshows four R-R peaks corresponding to four heartbeats and it can be seenthat a first electrical stimulation signal D′ (corresponding to D inFIG. 11A) is applied to the first electrode pair 14′, 16′ via channel 1during a first heartbeat. A second train of electrical stimulationpulses D″ is then applied during a second subsequent heartbeat via thechannel 2 to the pair of electrodes 14″, 16″. During the third heartbeata further train of electrical stimulation pulses D′″ is applied viachannel 3 to the third pair of electrodes 14′″, 16′″ and during a fourthheartbeat a further train of electrical stimulation pulses D″″ isapplied via the channel 4 to the fourth pair of electrodes 14″″, 16″″.During a fifth heartbeat (not shown) a further train of electricalstimulation pulses corresponding to D′ is again applied via channel 1 tothe first pair of electrodes 14′, 16′ and so on.

FIG. 16A again illustrates the offset between the two channel groupschannels 1 to 4 and channels 5 to 8, and it can be seen that thestimulation signal applied to muscle group 1, for example the musclegroup with which the electrode pair 14′, 16′ cooperates, has a durationwhich is considerably shorter than the muscle contraction which itgenerates.

In FIG. 11A and in FIGS. 16A and 16B there is shown a relativelystraightforward method of muscle stimulation involving five individualbiphasic pulses D. These five individual biphasic pulses are illustratedagain in FIG. 17A, together with possible values for the amplitude ofthe biphasic pulses in volts and durations shown in milliseconds.

It is, however, possible to use additional stimulating pulses after theinitial group of stimulating pulses D in order to prolong the musclecontraction but minimizing the electrical input into the patient whichis beneficial both for the patient and for the lifetime of the batteriesinvolved in the stimulation signal generators.

In the scheme shown in FIG. 17B the first group of pulses D is followedby individual pulses E, F which, in this example, are single biphasicpulses identical to the individual biphasic pulses of the group D, butwith a greater pulse interval between the pulses. In practice there canbe many more individual pulses such as E and F. Also there are a largenumber of different variants of such stimulation schemes and these areexplained in detail in WO 2005/044374. They will not be discussed herein detail.

1. An apparatus configured for cardio-synchronised stimulation ofskeletal or smooth muscle, but excluding the heart muscles, in acounterpulsation mode of a patient having a cardiovascular system and aheart having a heart rate, the apparatus comprising: at least one activeelectrode and at least one passive electrode configured for attachmentto said patient at positions at which the electrodes are incommunication with said skeletal or smooth muscle when said skeletal orsmooth muscle is in its original, natural position within the patient; asignal processor configured to produce control signal informationrelating to stimulation signals to be applied to said at least oneactive electrode in the counterpulsation mode; a sensing systemconfigured to sense information relating to performance of the patient'sheart, the information comprising at least the heart rate, and totransmit information signals to said signal processor; at least onestimulation signal generator associated with said active electrode andconfigured to generate the stimulation signals, the stimulation signalsbeing provided at the active electrode in synchronization with the heartrate in the counterpulsation mode to thereby stimulate the skeletal orsmooth muscle when the skeletal or smooth muscle is in the original,natural position within the patient; and a wireless transmitterconfigured to transmit said control signal information from said signalprocessor to said at least one stimulation signal generator, wherebysaid stimulation signal generator applies the stimulation signals tosaid active electrode in the counterpulsation mode in accordance withsaid control signal information.
 2. The apparatus in accordance withclaim 1, wherein said information relating to the performance of theheart is selected from the group consisting of heart rate information,electrocardiogram (ECG) information, ECG derived information, ECGinformation and information resulting from electrical stimulation, ECGderived trigger signals, R-R information, end of T-wave information,blood pressure information, and blood pressure derived information. 3.The apparatus in accordance with claim 1, wherein said sensing systemcomprises at least one of an invasive sensor, an intercavity sensor, anon-invasive sensor, a body surface sensor, and a remote sensing systemdetached from the patient's body.
 4. The apparatus in accordance withclaim 3, further comprising a remote sensing system, wherein said signalprocessor is integrated into said remote sensing system.
 5. Theapparatus in accordance with claim 1, further comprising a medicalevaluation unit.
 6. The apparatus in accordance with claim 5, saidsignal processor being adapted to transmit said information to themedical evaluation unit by one of wireless transmission and a wiredconnection.
 7. The apparatus in accordance with claim 5, said medicalevaluation unit being adapted to transmit signal configurationinformation to said signal processor by one of wireless transmission anda wired connection and said signal processor being adapted to takeaccount of said signal configuration information when generating saidcontrol signal information.
 8. The apparatus in accordance with claim 1,wherein the at least one of active electrode comprises a plurality ofactive electrodes and said at least one stimulation signal generatorcomprises a respective stimulation signal generator for each activeelectrode, said signal processor being configured to transmit arespective control signal uniquely associated with a respective one ofsaid active electrodes to each said stimulation signal generator.
 9. Theapparatus in accordance with claim 1, wherein said signal processor isconfigured to transmit control signal information for a train ofstimulation signals applied to one of the active electrodes, saidcontrol signal information being selected from the group consisting of:amplitude of the stimulation signals, frequency of the stimulationsignals, duration of the train of the stimulation signals, width of theindividual stimulation signals of the train delay of the train of thestimulation signals relative to a reference selected forcounterpulsation stimulation, and a recognition code by which saidstimulation signal generator recognizes that said control signalinformation is intended for it.
 10. The apparatus in accordance withclaim 9, further comprising a means provided at said signal processorfor receiving and storing at least one of a program for processing saidcontrol signal information, any subsequent changes to said program, anda new program for processing said control signal information.
 11. Theapparatus in accordance with claim 1, wherein the or each saidstimulation signal generator includes at least some of the followingitems: its own controller, its own clock, its own receiver antenna (RX),a power circuit, a battery, a transmitter (RX), means for data storage,means for program storage and a signal generator trigger.
 12. Theapparatus in accordance with claim 1, wherein a display is provided atat least one of said signal processor, said configuration inputassociated with the signal processor, said stimulation signal generatorand a medical evaluation unit associated with said apparatus, saiddisplay being for the display of at least said control signalinformation.
 13. The apparatus in accordance with claim 12, wherein saiddisplay is adapted to display data representing an image of theelectrical stimulation applied to said patient.
 14. The apparatus inaccordance with claim 13, wherein said display is adapted to display oneof an actual ECG-trace and a representation of an ECG-trace with saidimage superimposed thereon.
 15. The apparatus in accordance with claim5, wherein said medical evaluation unit has an associated printer forprinting said data.
 16. The apparatus in accordance with claim 1,wherein a code is uniquely associated with said sensing system, saidsignal processor, and said electrical stimulation signal generator. 17.The apparatus in accordance with claim 1, wherein said stimulationsignal generator comprises a member of the group consisting of a mobilephone, a personal digital assistant with phone function, and anydedicated or standard piece of equipment comprising a transceiver, amicroprocessor, a memory for storing software and data, a battery orother source of power, a clock, and necessary interface(s) forconnection to the active and passive electrodes.
 18. The apparatus inaccordance with claim 1, wherein said signal processor comprises amember of the group consisting of a mobile phone, a personal digitalassistant with phone function, and any dedicated or standard piece ofequipment comprising a transceiver, a microprocessor, a memory forstoring software and data, a battery or other source of power, and aclock.
 19. The apparatus in accordance with claim 5, wherein saidmedical evaluation unit comprises a member of the group consisting of isone of a personal computer, a mainframe computer, a series ofinterlinked computers, any of the foregoing with an inbuilt transceiver,a personal digital assistant with phone function, and any dedicated orstandard piece of equipment comprising a transceiver, a microprocessor,a memory for storing software and data, a battery or other source ofpower, and a clock.